1998 and "L65"???

[DennisG01]

Just wondering about this - when some people are talking about L65 engine programming, they usually refer to it being offered in the 1999 model year. Am I looking in the right spot to see if I have this? I see an L65 code in my glove box. My truck does have a later build date in the 1998 model year. Thanks!

[Turbine Doc]

L65 is HD engine option (non EGR) letter #8 in VIN is either F for L65 or S for L56, 99+ years GM did some performance enhancements to the PCM for 215Hp IIRC up from 195

[DennisG01]

Thanks, Tim.

What sort of things go into the making of an L65 engine that differentiate it from an L56?

[DA BIG ONE]

Originally posted by tbogemirep:
L65 is HD engine option (non EGR) letter #8 in VIN is either F for L65 or S for L56, 99+ years GM did some performance enhancements to the PCM for 215Hp IIRC up from 195 So, in the case of those of us who have the 99 L65, what would be considered a safe boost level with an IC, and what egt's should we lookin for?

[rjschoolcraft]

The 215 HP rating never made it to production. The 99 L65's had 195 HP same as the 98's. As far as safe boost goes, there's lots of debate. I run 17 psi max (at around 800 - 1200 ft. elevation) now. Read about it here: 6.5 Performance (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=006650).

[Turbine Doc]

Thanks for clarification Ronnie it's an oft discussed thing this 215 Hp program, never knew if it were true or not.

One thing I'll add though on my scanner; max fuel delivery was 63mm with the 98 L56 program, on the 99 L65PCM I would see up to 76mm, so for a L56 truck to L65 program there is a gain, maybe L65 to L65 HD rated trucks there is no change year to year.

Both the stock L56 & L65 have the wussily boost curve/fuel cut back that only momentarily bump max boost & fuel before settling at what PCM/GM thinks is best.

Which by the way is right when you need extra power most. Reflash/chip IMO only cure for that, a boost control helps in boost cutback but does not add fuel, it does make more of what fuel is in program available for use though.

Dennis mostly L56 is EGR stuff on 1500 or LD rated 2500s, another way the guvmint sticks it to us, (we don't need no power in a LD rated truck) so we are going to choke it with power robbing devices to satisfy the tree hugging contingent of society.

My VW TDI has maintenance problems with EGR stuff to the point of making the vehicle undriveable, the cat & intake on a L56 truck suffers same problem it will eventually gunk up, happens faster on the TDI as it's overall smaller.

Diesels by nature don't produce harmful emmissions that a gasser does but it does emit visible "smoke" which "must be controlled" if it smokes it must be bad which is why we have L56's we don't really need maybe why there isn't a LD offering in the DMax world.

Unfortunately tree huggers have a strong lobby & even though the facts show Diesels run better without this junk all will soon have them.

I'm even hearing rumors in my world of "green jets" that are causing all sorts of reliability issues.

Sorry to digress, L56 has EGR, reduced flow intake, lower fuel delivery at least it looks that way on my scanner, and catalyst. When I set up for off road running my truck does run better without that stuff when I off road.

(I would never myself, nor recommend it to another, disable the environmentally saving devices the gov-mint says I have to have)

I will fess up that every once in a while I forget to reconfigure for on road use; it runs better on road without that stuff also.

[ 07-01-2004, 08:55 AM: Message edited by: tbogemirep ]

[99gmccrew]

I thought I had the 215hp that gm lead us to believe, would be on the 99 6.5l. Ronniejoe quickly informed me that this upgrade never made it to production and it appears he is correct. I search for the hp rating and I had trouble locating it. Joeyd pointed me in the right direction in finding the hp rating, listed on airfilter box, duh!. There it was 195hp @ 3400 rpm. :(

[triggerman]

Tim,
At least on the VW you can reprogram (w/$200 VAG-COM) the PCM to vastly minimize EGR function with no codes set! :D

[norm]

My '95 L65 came with catalyst - I am not sure if they all did all years. Maybe the top kicks or med. duty trucks did not I am not sure.

[Turbine Doc]

Norm, I believe there are HD & LD 2500s I would suspect you have a LD 2500 which were EGR equipped.

Walt you sell the Tahoe yet I think I saw where diesel realtor is looking for one.

[norm]

Tim,
I have a 3500 (one ton, not light duty, but not DRW) with H.O. L65 engine - no EGR, but yes it came with converter. They likely all did, except maybe a cab/chassis or some other heavy version without converter.

Norm

[triggerman]

Tim,
A guy is coming up from Tennessee to pick it up Tuesday. I already bought a 01 Dodge/Cummins Quad/cab SB 4x4, AN Lovin it! Rides rough, but what an engine!

[ees]

Well after reading this thread I am curious. I have a cat/filter in my exhaust, but I don't have EGR. Did this start a certain year or was it just on the LD engine throughout the years?

One of these days Helm will get off their butts and print me a manual. Then I might know a little more about this truck. (Been on order for months).

[Marty Lau]

I have L56 and the owner manual said it was rated at 190hp@3400 I believe the L65's have the 195hp rating.
All the 1500 trucks I believe are L56 and the "standard duty" 2500 also L-56. The "Standard 3/4ton" have the 6 bolt rear wheels, heavy duty 3/4 8 bolt wheels. Just a quick way to ID.

[patrick m.]

my hd 2500 (8 lug) had a cat.
all the ones i have seen have the cat
.......havent seen very many duallys, so cant remember.
my truck is certainly the HD 2500 hub mounted front rotors, 8 lug, 9 inch front diff, 10.5 inch rear diff, full floating axles, blah,blah,